Second, the welfare function welf (REF ) of [1]} is used in reciprocal recommendation as a single sum: \(F^{\it welf} (P) = \sum _{i=1}^n \phi (u_i(P), \alpha )\)  where \(\phi \)  is defined in Sec. REF . We study welf as baseline by varying \(\alpha ,\)  which controls the redistribution of utility in the user population.
